1. Field of the Invention
The present invention is generally related to a method for forming basic nickel carbonate, and more particularly to a method for forming basic nickel carbonate using sodium carbonate and sodium bicarbonate.
2. Description of the Prior Art
Nickel is very important material in the electronic industry and the livelihood, especially plating nickel demand is quite large and the process is quite common, and its demand is all over the integrated circuit and printed circuit board industries. In particular, for the nickel plating process commonly used as additives for adjusting the pH value of the plating solution and adding the nickel content.
Basic nickel carbonate is an important inorganic fine chemicals, it is mainly for the preparation of a variety of nickel salt. It is widely used in electroplating, electroforming, enamel paint and industrial catalysts and other industries. Besides the high quality of basic nickel carbonate can be used in electronics industry.
There are advantages of a simple process for preparation of powder materials by liquid phase reaction to generating precipitation method. It is a widely used method. However, in the current industrial production process, for selecting of the raw material and controlling of process conditions and so on, basic nickel carbonate samples prepared, the impurity is not only high content but also difficult to removal in the washing process. It could not meet the needs of high-purity raw material needs in the industry. To solve the above problem, it is used a solution for nickel raw materials and sodium carbonate as precipitant, to explore a continuous synthesis of high-purity basic nickel carbonate process method. Through the choice of raw materials nickel and the conditions of process control, the powder surface of basic nickel carbonate is smooth, and the powder internal is compact, and the powder package less impurities. After washing, it could obtain a high purity product of basic nickel carbonate.
In addition, nickel carbonate is an important compound of nickel. There are known morphology such as nickel carbonate, basic nickel carbonate and nickel carbonate acid. Usually it is obtained by nickel nitrate and sodium carbonate aqueous solution. The difference of preparation methods is obtained different compound. One composition is written as xNiCO3.yNi (OH) 2. zH2O, it is a pale green amorphous material. Pure nickel carbonate and nickel carbonate acid are less, and the basic nickel carbonate is mainly. The most common composition is written as NiCO3.Ni(OH)2.H2O; NiCO3.2Ni(OH) 2.4H2O.
Basic nickel carbonate is mainly used to three main areas: (1) the inorganic intermediate product, prepared as other nickel salts: nickel acetate, nickel sulfamate, catalysts, other organic nickel salt intermediates prepared; (2) preparation of nickel oxide calcined or further reduced to nickel powder, for magnetic materials and carbide; (3) electroplating materials, ceramic pigments and the like.
Production of basic nickel carbonate is mainly synthesized by aqueous solution that is comprised sodium carbonate in nickel nitrate or nickel sulfuric acid, it was also using ammonium bicarbonate as a replace of sodium carbonate. Some studies use a precipitation of nickel ammonium carbonate, a precipitation of carbonate and a precipitation of high concentrations of urea to prepare basic nickel carbonate.
Nowadays, production plant produced nickel carbonate with high impurity, and nickel content is low. It is difficult to meet the requirements of high-quality nickel. Moreover the production is a long time for hot water washing process, and high energy consumption. It is consumed a large amount of water, 1 ton product is needed 80-100 tons of washing water and a lot of coal. There are first washing, first drying, secondary washing, secondary drying, and grinding in the production of process. By the process, the product of nickel carbonate have lower sodium, lower chloride, and lower sulfate. Another production process, the materials of coarse nickel carbonate is conducted flash drying by spinning flash dryer, it is shown a villous or floc particles, and it is a non-pure nickel carbonate which contents the sodium. Then nickel carbonate is conducted the dried process and then nickel carbonate is added in the slurry washing tank with 60-80° C. pure water. It is conducted washed slurry. By pressure filtration, it is get the carbonate nickel products removed sodium. After washing, sodium which contented in nickel carbonate is dropped about 20%-40% than before washing. It is reduced the content of sodium (Na content of 0.05 to 0.1%). It meets production requirements. There are studies for the above-mentioned problems, a continuous washing equipment with dry process, it could greatly reduce the washing time and hot pure water, while reducing the sodium content (<0.01%). Meanwhile, the reaction materials which comprise nickel sulfate and sodium carbonate are discussed.
Current research related to the preparation technology of the basic nickel carbonate is extremely rare in Taiwan. Production of basic nickel carbonate is also mostly small-scale manufacturers, the main source of the basic nickel carbonate is from mainland China. At present the main synthesis technology use NiSO4 as a source of nickel. NiSO4 with Na2CO3 reacts into basic nickel carbonate. In addition to Na2CO3, some synthesis use ammonium bicarbonate (NH3HCO3). The nickel content of the synthesis of the basic nickel carbonate are less than 50% (mass %).
So, how to produce low-cost basic nickel carbonate, and the production of basic nickel carbonate can improve the problem of dust, avoid agglomeration, keep good liquidity, has the faster rate of dissolution in acid, and increase yield. Current industry demand is still eager to improve on the industry.